Acute ischemic stroke (AIS) is one of the most common nervous system diseases. Its high mortality and disability rates not only seriously threaten patients' health but also impose a significant socioeconomic burden. Intravenous thrombolysis (IVT) is the first-line treatment for AIS, and tissue-type plasminogen activator (t-PA) is the primary agent used in IVT. With the extension of the therapeutic time window, more AIS patients are eligible to receive t-PA treatment. The existence of thrombolytic resistance severely compromises the clinical efficacy of t-PA in AIS treatment. This paper elaborates on the phenomenon of thrombolytic resistance and analyzes the roles of thrombus components such as red blood cells (RBCs), platelets (PLTs), white blood cells (WBCs), and neutrophil extracellular traps (NETs), as well as non-thrombotic factors such as metabolic syndrome (MetS) and fatty acid (FA) in contributing to thrombolytic resistance. By clarifying the underlying mechanisms of thrombolytic resistance, this work aims to provide insights for strategies to overcome thrombolytic resistance and improve the therapeutic efficacy of t-PA.

PurposeThe study aims to assess the outcomes of introducing tissue plasminogen activator (t-PA) for massive subretinal hemorrhage (SRH) during pars plana vitrectomy (PPV).MethodsThis consecutive, retrospective, non-randomized study evaluated 11 eyes with massive SRH. The post-operative follow-up was assessed after 3- and 6 months from the surgery, evaluating the Best-corrected visual acuity (BCVA) and measured the central macular thickness (CMT). All eyes were undergoing a PPV in combination with t-PA introduction and retinal displacement, fluid-air exchange, and anti-VEGF injection.Results11 eyes were included. At baseline, the main BCVA before the surgery was very poor. At 3-month after the surgery 5 eyes (45.4%) gained two and three lines on the visual acuity chart (range 20/400-20/100), and it was remained stable at 6-month. Solely in 3 eyes the BCVA not improved in the follow-up time. Moreover, in 3 eyes (27.3%), the BCVA improved significantly (p < 0.05). Pre-surgical CMT was 596,4 ± 143,2 μm. Postoperative CMT was 288,7 ± 77,6 μm at 3-months follow-up (p < 0.05) and 263,3 ± 75,2 μm at 6-months follow-up (p < 0.05). Hemorrhage was displaced away from the fovea in all eyes. SRH recurred in only one eye.ConclusionWe suggest that timely intervention in massive-sized SRH may play a crucial role in limiting the extent of damage and preventing poor visual outcomes. It is also important to note that prompt treatment may help preserve foveal anatomy and limit the structural damage associated with this condition.

Isotope substitution is widely used to probe phonon behavior in hydrogen-rich materials, yet its effects on phonon dispersion remain difficult to access and poorly understood, particularly in low-dimensional systems. Here, using trans-polyacetylene (t-PA) as a prototypical model, we theoretically demonstrate tip-enhanced Raman scattering (TERS) imaging as a real-space approach for visualizing isotope effects on phonon dispersion. To enable a complete comparison between hydrogenated and deuterated t-PA, we access all optical phonon branches by activating the normally Raman-forbidden out-of-plane modes through the field-gradient effect. The newly resolved out-of-plane branches exhibit a crossing after deuteration, arising from their distinct wavevector-dependent isotope responses. By introducing the hydrogen-site mass participation factor, we show that phonon modes with stronger hydrogen-site motion undergo larger isotope-induced red shifts, whereas its wavevector-dependent variation governs dispersion reshaping and branch crossing. Moreover, Raman images directly visualize the deuteration-induced redistribution of vibrational amplitudes associated with hydrogen-site motions, thereby revealing the microscopic origin of isotope effects on phonon dispersion. These findings establish TERS imaging as a powerful real-space approach for visualizing isotope-dependent phonon behavior in low-dimensional molecular systems.

The aim of this study was to determine, in vitro, the effect of endothelial cell-derived extracellular vesicles (EEVs) from adults with obesity on brain microvascular endothelial cell nitric oxide (NO) and endothelin (ET)-1 production as well as tissue-type plasminogen activator (t-PA) release. Circulating EEVs (CD144+ extracellular vesicles) were identified, enumerated, and isolated (flow cytometry) from 24 midlife and older sedentary adults (45-71 yr): 12 normal weight [6 M/6 F; body mass index (BMI) ≥18.5 and ≤25 kg/m[2]] adults and 12 adults with obesity (6 M/6 F; BMI ≥ 30.0 kg/m[2]). Human cerebral microvascular endothelial cells (hCMECs) were cultured and treated with EEVs from either normal-weight adults or adults with obesity. Expression of phosphorylated (p)-eNOS (Ser1177) was ∼20% lower (31.5 ± 5.6 vs. 39.1 ± 7.9 AU) and p-eNOS (Thr495) expression ∼40% higher (47.3 ± 13.2 vs. 33.4 ± 10.5 AU) in hCMECs treated with EEVs from obese compared with normal weight adults. As a result, NO production was significantly lower (∼20%) in hCMECs treated with EEVs from adults with obesity (4.9 ± 0.4 vs. 5.9 ± 0.5 µmol/L). Cell expression of Big ET-1 (317.8 ± 51.8 vs. 241.6 ± 65.0 AU) and endothelin-converting enzyme (838.3 ± 160.8 vs. 631.8 ± 126.3 AU) as well as ET-1 production (21.9 ± 1.6 vs. 18.0 ± 3.9 pg/mL) were significantly higher in hCMECs treated with EEVs from adults with obesity. t-PA release in response to thrombin was significantly lower in hCMECs treated with EEVs from obese (from 49.3 ± 6.6 to 52.3 ± 8.2 pg/mL) compared with normal weight (from 52.3 ± 8.8 to 62.0 ± 8.1 pg/mL) adults. Circulating EEVs are a potential mediator of obesity-related cerebrovascular dysfunction and stroke risk.NEW & NOTEWORTHY Despite an improved understanding of many of the pathological consequences associated with human obesity, factors that initiate, promote, and accelerate cerebrovascular events are not completely understood. This study provides novel data demonstrating that circulating EEVs from adults with obesity adversely affect eNOS activity, reducing nitric oxide bioavailability, enhancing ET-1 production, and impairing t-PA release in brain microvascular endothelial cells in vitro. These changes in endothelial cell phenotype have been linked with cerebrovascular dysfunction and ischemic stroke risk.

In recent years, artificial placenta systems have been developed for the clinical treatment of infant respiratory distress syndrome (RDS). Their use requires systemic anticoagulation to prevent clotting during treatment. However, this approach significantly increases the risk of intracranial hemorrhage in premature infants. Therefore, suitable surface modification is needed to eliminate the need for systemic anticoagulants. We have developed a dual-modification method based on an antithrombin-heparin complex (ATH) and tissue plasminogen activator (t-PA) using polydopamine as a surface linker to attach the molecules to polydimethylsiloxane (PDMS) surfaces. The resulting materials were previously shown to have enhanced anticoagulant properties, believed to be through a synergistic effect between the two molecules. The polydopamine-linked coating can be used with a variety of materials and shows promise in applying these modifications to complex structures. Here, we translated this modification method to a PDMS microfluidic oxygenator system that constitutes the artificial placenta. Scanning electron microscopy (SEM) demonstrated successful modification of the microfluidic units, and radiolabeling data showed that the dual bioactive modification was uniformly distributed within the device. The surface density and stability of the immobilized biomolecules were similar to those found previously for the same modifications on simple PDMS discs, suggesting that they should have similar anticoagulant effects in the oxygenator. This was confirmed using human plasma and whole blood, in which the dual-modified oxygenator showed a significant increase in anticoagulant properties. It was also demonstrated that the surface modifications did not affect the oxygenator's gas exchange capacity. These results indicate that this bioactive surface modification approach shows promise for use in clinical artificial placenta systems. STATEMENT OF SIGNIFICANCE: Antithrombin-heparin (ATH) and tissue plasminogen activator (t-PA) are promising biomolecules for antithrombotic surface modification. In this work, methods have been developed to modify polydimethylsiloxane (PDMS) single microfluidic oxygenator units with both ATH and t-PA, and to evaluate the modification properties, antithrombotic activity, and oxygen exchange capacity of the surfaces after modification. A uniform coating was formed in the oxygenator unit, and synergism between ATH and t-PA on the surface resulted in enhanced antithrombogenic activity. This dual modification approach using polydopamine (PDA) as a priming layer has significant potential for achieving long-term antithrombogenicity of microfluidic lung assist devices and other medical devices.

The aim of this study was to determine, in vitro, the effect of endothelial cell-derived extracellular vesicles (EEVs) from older adults on brain microvascular endothelial cell oxidative stress, inflammation, nitric oxide (NO) and endothelin (ET)-1 production, as well as tissue-type plasminogen activator (t-PA) release. Circulating EEVs (CD144[+] extracellular vesicles) were enumerated and isolated (flow cytometry) from the plasma of 30 healthy, sedentary, nonobese adults: 15 young (age: 21-35 yr; 7 M/8 F) and 15 older (55-80 yr; 7 M/8 F). Human cerebral microvascular endothelial cells (hCMECs) were cultured and treated with EEVs from either group. EEVs from older adults induced higher reactive oxygen species (ROS; 140 ± 51 vs. 99 ± 16% of control; P = 0.02) production and lower expression of catalase [13.7 ± 3.7 vs. 23.2 ± 7.4 arbitrary units (AU); P < 0.01] and superoxide dismutase-1 (SOD-1; 147.6 ± 41.1 vs. 281.2 ± 78.3; P < 0.01) in hCMECs than EEVs from young adults. EEVs from older adults did not induce cellular inflammation. Expression of phosphorylated (p)-endothelial nitric oxide synthase (eNOS) (Ser1177) was significantly lower (61.6 ± 13.0 vs. 77.7 ± 17.6 AU), p-eNOS (Thr495) was significantly higher (49.9 ± 16.4 vs. 38.0 ± 10.9 AU), and NO production (5.9 ± 1.6 vs. 7.3 ± 1.3 µmol/L) was significantly lower in hCMECs treated with EEVs from older adults. Big ET-1 (95.3 ± 17.1 vs. 69.4 ± 20.6 AU; P < 0.001) and endothelin-converting enzyme (ECE; 164.8 ± 26.0 vs. 128.4 ± 18.5 AU; P < 0.001) expression as well as ET-1 production (27.3 ± 9.1 vs. 21.2 ± 5.5 pg/mL; P = 0.03) were significantly higher in hCMECs treated with EEVs from older adults. t-PA release in response to thrombin was significantly lower (∼30%) in hCMECs treated with EEVs from older adults. Circulating EEVs represent a potential mechanistic factor contributing to increased stroke risk with aging.NEW & NOTEWORTHY Aging is the preeminent risk factor for ischemic stroke. The mechanisms underlying the age-related increase in stroke risk and incidence are complex, diverse, and not completely understood. This study provides novel data implicating circulating endothelial cell-derived extracellular vesicles (EEVs) as a novel mediator of age-related cerebrovascular disease and events. EEVs from older adults increased oxidative stress, compromised nitric oxide bioavailability, enhanced ET-1 production, and impaired t-PA release in brain microvascular endothelial cells in vitro.

The experimental aim of this study was to determine, in vitro, the effect of estrogen on brain endothelial cell oxidative stress, apoptotic susceptibility, and tissue-type plasminogen activator (t-PA) release. Human cerebral microvascular endothelial cells (hCMECs) were cultured and treated with 17β-estradiol (100 nM), the primary and most biologically active endogenous form of estrogen in humans, for 24 h. Intracellular reactive oxygen species production was significantly lower (∼15%; P > 0.01) in hCMECs treated with 17β-estradiol; however, antioxidant proteins superoxide dismutase-1 (28.6 ± 11.0 vs. 36.2 ± 11.9 AU) and catalase (33.6 ± 14.0 vs. 32.1 ± 14.7 AU) were not significantly altered by 17β-estradiol. Although, there were no significant differences in the basal intracellular expression of either total caspase-3 (159.8 ± 84.9 vs. 143.6 ± 39.2 AU) or active caspase-3 (13.5 ± 4.5 vs. 15.4 ± 6.7 AU) between untreated and 17β-estradiol-treated hCMECs; the increase in active caspase-3 in response to the apoptosis stimulus staurosporine was significantly lower (∼30%; P = 0.02) in 17β-estradiol-treated (from 15.5 ± 6.7 to 184.5 ± 43.8 AU) compared with untreated (from 13.5 ± 4.5 to 257.6 ± 34.4 pg/mL) hCMECs. t-PA release in response to thrombin was significantly higher (P = 0.02) in 17β-estradiol-treated (from 41.6 ± 10.8 to 61.1 ± 9.2 pg/mL; ∼45% increase) compared with untreated (43.4 ± 9.2 to 48.0 ± 11.5 pg/mL; ∼10% increase) hCMECs. In summary, 17β-estradiol decreases oxidative stress, enhances apoptotic resistance, and increases fibrinolytic capacity in human brain microvascular endothelial cells in vitro. Reduced risk of cerebrovascular disease and thrombotic events attributed to estrogen may be mediated, in part, by these beneficial endothelial effects.NEW & NOTEWORTHY The cerebrovascular protective effects of estrogen are diverse, complex, and not fully understood. This study provides novel data demonstrating that 17β-estradiol decreases oxidative stress, enhances apoptotic resistance, and increases fibrinolytic capacity in human brain microvascular endothelial cells in vitro. These changes in endothelial cell phenotype have been linked (clinically and epidemiologically) to less cerebrovascular dysfunction and reduced ischemic stroke risk.